Processes for breaking petroleum emulsions



J1me 1951 M. DE GROOTE ETAL 2,558,511

PROCESSES FOR BREAKING PETROLEUM-EMULSIONS Filed NOV. 1, 1949 MW W MMA MELVIN DE GROOTE ARTHUR F. W/RT'EL A TTORNEY UNITED" STATES F'PATENT OFFICE PROCESSES FOR BREAKING PETROLEUM EMULSIONS Melvin De Groote, University City, and Arthur F. Wirtel and Owen H. Pettingill, Kirkwood, M0,, assignors to Petrolite Corporation, Ltd., Wilmington, DeL, a corporation of Delaware Application November 1, 1949, Serial No. 124,813

5 Claims. (Cl. 252-331) This invention relates to processes or procedures particularly adapted for. preventing, breaking or resolving emulsions of the water-inoil type, and particularly petroleum emulsions.

Complementary to the above aspect of the in-' vention herein disclosed, is our companion invention concerned with the new chemical products or compounds used as the demulsifying agents in said aforementioned processes or procedures, as well as the application of such 'chemi cal compounds, products, or the like, in various other arts and industries, along with the method for manufacturing said new chemical products or compounds which are of outstanding 'value in demulsification. See our co-pending application Serial No. 124,814, filed November 1, 1949.

Our invention provides an economical and rapid process for resolving petroleum emulsions of the water-in-oil type, that are commonly referred to as cut-oil, roily oil, emulsified oil, etc., and which comprise fine droplets of naturally-occurring waters or brines dispersed in a more or less permanent state throughout the oil which constitutes the continuous phase of the emulsion.

It also provides an economical and'rapid process for separating emulsions which have been prepared under controlled conditions from mineral oil, such as crude oil and relatively soft waters or weak brines. Controlled emulsification and subsequent demulsification, under the conditions just mentioned, are of significant value in removing impurities, particularly inorganic salts, from pipeline oil.

Demulsification, as contemplated in the present application, includes the preventive step of commingliing the demulsifier with the aqueous component which would or might subsequently become either phase of the emulsion, in the absence of such precautionary measure. Similarly,

para-menthylcyclohexanol with ethylene oxide and propylene oxide within the limits and manvner hereinafter specified.

It is well known that a variety of compounds .containing a reactive hydrogen atom, i. e., a

hydrogen atom attached to oxygen, nitrogen, or sulphur will react with alkylene oxides, particularly ethylene oxide or propylene oxide, to yield the corresponding glycol or polyglycol derivative.

.Such oxyalkylated derivatives are readily prepared from chemical compounds, in which the hydrogen atom is directly attached to oxygen,

2 and particularly, in the case of alcohols or phenols, such as aliphatic alcohols, phenols, alkylaryl alcohols, alicyclic alcohols, phenoxyalkanols, substituted phenoxyakanols, etc. Generally speaking, it has been found advantageous to react a water-insoluble hydroxylated material, having 8 carbon atoms or more, with an alkylene oxide so as to introduce water-solubility, or at least, significant or distinct hydrophile character, with the result that the derivative so obtained has surface-active properties. Examples of suitable reactants of this-type include octyl alcohol, decyl alcohol, dodecyl a1- cohol, tetradecyl alcohol, octadecyl alcohol, butylphenol, propylphenol, propylcresol, hexylphenol, octylphenol, nonylphenol, and cardancl, as well as the corresponding alicyclic alcohols obtained by the hydrogenation of the aforementioned phenols. It has been suggested that such materials be used in the resolution of petroleum emulsions. As far as we are aware, none of such materials represent products which are acceptable in demulsification today, from a competitive standpoint. In the majority of cases, such prodmaterial basis, or same cost basis.

Reference is made to our copending application Serial No. 124,811, filed November 1, 1949.

We have discovered a very few exceptions to the above general situation. For example, we have discovered, if one treats paramenthylcyclohexanol with ethylene oxide and propylene oxide so as to yield a cogeneric mixture of glycol ethers, that such mixed derivative has unusual properties, provided that the composition lies Within a certain range, as hereinafter specified. A specific exemplification of this range is the product obtained by treating one mole of paramenthylcyclohexanol with 23 moles of propylene oxide, and then with 27 moles of ethylene oxide. Similarly, one may treat the para-menthylcyclohexanol with the 27 moles of ethylene oxide first and then with the 23 moles of propylene oxide next;

In subsequent paragraphs from time to time reference is made to compounds or cogeneric mixtures. At first glance, it may appear that such language is indefinite, and perhaps, contradictory. It is the intention at the moment only to point out that there is no inconsistency in such description, and that, subsequently, there graphically. These para-menthylcyclohexanol ether mixtures do 'not appear to be universally competitive, and, as a matter of fact, appear to be highly selective in regard to their action as demulsifying agents. However, such ,products have significant utility in a number of different oil fields where they serve better than any other available demulsifying agent. Theinutility may;

of course, increase as time 'goes along.

Para-menthylcyclohexanol is obtained by the 1 hydrogenation of menthylphenol. The procedure is essentially the same as iemployed in the con-" version of phenol to cyclohexanol. The formula of menthylphenol is believed to be as follows:

"The product obtained by hydrogenation is, :of course, the corresponding cyclohexanol, to wit,

menthylcyclohexanol, the iformula=of which :is :as follows -'The :molecular weight of :para menthylcyclohexanolis 232; the commercial'produc't actually shows :a molecular weight slightly more. For

convenience, we have taken the "molecular weight' iofithe commercial product as 238.

It is'very peculiar that the effectiveness of the demulsifying agents herein described seem to be limited 'to a very narrow range, or area, as far as composition goes. scribed by reference'to :the accompanying drawing which illustrates, in conventional graphical form, compositions used-in accordance with the inventionin terms of the three components. The figure is a conventional triangular graph showing compositions in "terms of the three components. Thus, the drawing illustrates glycol ethers of para-menthylcyclohexanol, or cogeneric "menthylcyclohexano'l and propylene oxide alone, 'or para-menthylcyclohexanol and ethylene oxide, in terms of the initial reactments. We have found that effective demulsifying agents lie approximately within a small and hitherto unsuspected area indicated by the trapezoid determined by the points :8, 9, l and N. More specifically, particularly effective demulsifying agents-appear within-a smaller range, as set'forth approximately by the area indicated by the seg- "mentof a circle, 'in which the area of the segment is limited to derivatives in which menthylcyc'lohexanol contributes at least 4% by weight of the ultimatecompound.

The circle itself is identified by the fact'that the points l, i3 and 6 appear on the circle. The more effective of these better compounds or cogeneric-mixtures'are those which appear with- ".-inithe triangle which represents :partof the circle and part of the segment, to wit, the triangle The invention will be :del mixtures thereof, derivable from 'para-menthylcyclohexanol and ethylene oxide alone, or para-- identified by the points i, 3 and '6. "The most efiective compounds or .cogenericz-mixtures of all are those which fall within the inner central :triangle of the larger outer triangle identified .by the .points 1., 3 and 6, to wit, the smaller triangle identified by the points 2, 4 and '5. The most outstanding of these effective compounds .or :fco'g'eneric mixtures is one which appears to fall'substantially at the center of the smallerftriangle identified by point 1. This particular "point is obtained by treatin one mole -.of paramenthylcyclohexanol with 23.5 moles of propylene oxide, followed by treatment with 27.5 moles'of ethylene oxide.

In spite of the unique character of the compounds previously described, we "have'made addiitionally an invention withirian invention. 'This .canibe illustrated by lreference to 'thecompounds or cogeneric mixtures whose composition is determined'byrthe inner triangle'2, 4,5. This pre- 'ferred class of derivatives, or, for 'thatmatter, all the herein described products, can be made in three different ways: (a') by adding propylene oxide first and then ethylene oxide; (13) by adding ethylene oxide first and then propylene oxide; .or (c) by adding the two oxides .at random, indifferent, or uncontrolled addition so as :to produce a polyglycol ether in which the propylene .radicals .or ethylene radicals do not appear in continuous succession, but are'heterogeneously distributed.

The present invention represents the invention within theinvention referred to in our aforementioned co-pending application Serial 'No. 124,811, filed November 1, 1949. We have found that much more effective demulsifiers are obtained by adding the propylene oxide first andsubsequently .addingithe ethylene oxide, rather than some other procedure, such as addingthe ethylene oxide first and then the propylene oxide or a mixed addition. Thisisparticularlytrue in regard to the compositions coming'within the segment of the circle'previously referred to in the drawing.

As an illustration of the preparation of various compounds or cogeneric mixtures and particularly the most desirable ones, and also those which are helpful'in setting the limits in the graph previously referred to, the following examples are included: In connection with these examples, it will be notedthat the oxyalkylation of para-men: .thylcyclohexanol is conventional. The procedure is conducted in the same manner employed in connection with other alcohols, or the like, and generally, an alkaline catalyst is employed. See, for example, U. 8. Patent No. 2,440,093, dated April "20, 1948, to Israel, and British Patent No. 602,591,

applied for February 12, 1945.

Example 1 The reaction vessel employed'was a stainless :steel autoclave with the usual devices for heating, heat control, stirrer, inlet, outlet, etc., which is conventional in this type of apparatus. Thecapacity was approximately 40 gallons. The stirrer hold the tempera *tion as rapidly'as added; The amount 'ofpro- -.pylene oxide added was 136 pounds. The time required to add this propylene oxide was slightly in excess of one hour, about 1% hours. During propylene oxide there was added ethylene oxide,

- as previously indicated. The amount of ethylene oxide added was 120.5 pounds. The temperature employed, and operating conditions, were the same as withthe addition of propylene oxide. It

is to be noted, however, that ethylene oxide aptions were substantially the same as on a larger scale. Actually, the reaction seemed to go faster in the small autoclave and the time of absorption could be reduced, if desired. In many instances, absorption would take place in the laboratory autoclave in a fraction of the time required in the larger autoclave; in fact, in many instances, absorption was complete in to or minutes, as compared to one hour on alarger scale. Needless to say, on a large scale, addition must be conducted carefully because there is an obvious hazard in handling a large quantity of material in an autoclave which is not necessarily present in the use of a small vessel.

pears to be more reactive and the reaction seems 15 The data are summanzed 1n the following to require a greater amount of 13001111,; water to 1 table:

Propylene oxide Ethylene oxide Point on We'ght P t Gdraph 1 er en ti- Molal Weight We1ght 1 a Usedm Ratio m Fmal Weight Per Cent Weight Per Cent -3 Grams Glywl Used, in M1?1 in Final Used, 111 in Final Speclflc Ether Gra ns Rat) Glycol Grams Ram) Glycol a?? Ether Ether t 239 1. 0 15. 0 1 715 12.32 45 535 14. 43 1 233 1.0 10.0 1,192 20.55 50 953 21.55 40 2 23s 1. 0 5. 0 2, 520 45. 15 55 1, 910 43. 3 40 a 233 1. 0 10. 0 1, 071 13. 50 1, 071 24. 3s 45 V 4 235 1.0 5.0 2,332 41.1 2,140 43.5 45 5 23s 1. 0 5. 0 2, 145 37. 0 45 2, 330 54. 2 50 5 23s 1. 0 s. 5 1, 350 23. 42 45. 5 1, 205 27.4 43 7 235 1.0 9.2 1,255 21.54 45.5 1,092 24.32 42.2 23s 1. 0 9. 0 1, 255 1 21. 52 47. 4 1, 154 25. 2 43. 5 1 23s 1. 0 s. s 1, 24s 21. 5 45. 2 1,218 27. 45.0 1 233 1. 0 s. 5 1, 355 23. 3s 49. 0 1, 202 27. 3 43. 4 233 1; 0 3. 5 1, 350 23. 42 43. 5 1, 205 27.4 43. 0 4 7 235 1.0 3.4 1,321 22.75 45.5 1; 275- 29.0 45.0 23s 1. 0 s. 2 1, 43s 24. 75 49.5 1, 230 27.95 42. 3 23s 1. 0 s. 0 1, 444 24. 55 43. 5 1, 295 29. 4 43. 5 1 235 1.0 7.5 1,445 24.90 47.4 1,370 31.15 44.5 1 23s 1. 0 7. 0 .555 25. 72 49. 0 1, 495 33.05 44.0 1) 23s 1. 0 5. 0 1, 955 33. 90 45. 5 1, 755 40. 2 44. 5 238 1.0 20.0 309 5. 33 25.0 543 14.5 54.0 13 23s 1. 0 4. 0 1, 545 25. 7 25. 0 4,170 94. 7 70. 0 1 9 23s 1. 0 4. 0 4, 520 77. s 75. 0 1, 190 27. 0 20. 0 1 10 23s 1. 0 20. 0 714 12. 3 50. 0 23s 5. 42 20. 0 1

1 Within inner triangular area.

I Duplicated for convenience.

3 Indicates limits of trapezoidal area. ture range, as indicated. The time required to add the ethylene oxide was about the same, or slightly less, usually just a little more than an hour.

During the addition of the oxides, the pressure was held at approximately 50 pounds per square inch gauge pressure, or less. 1 When all the oxide had been added (ethylene oxide being the final addition in this particular instance) the autoclave was permitted to stay at the same temperature range for another half hour, even longer, if required, or until the gauge pressure had been re.-

- duced to zero, or substantially zero, indicating the :1

reaction was complete.

Y The final product'was an oily material, somewhat viscous in nature, and having a sort of greenish hue, without any definite odor. It was 1 dispersible in water and solublein non-aqueous solvents, such as aromatic hydrocarbon and others, although not soluble in some non-polar hydrocarbon solvents. The final yield was substantially the total weight of the initial reactants.

"' .Ezcamplez "'menthylcyclohexanol employed was 47.6 grams, the amount of propylene oxide employed was 272 grams, and the amount of ethylene oxide employed was 241 grams. The amount of caustic =soda employed 2.4 grams; The operating condi- In the preparation of the above compounds the alkaline catalyst used was either flake caustic soda finely ground with mortar and pestle, or

I powdered sodium methylate, equivalent to 5% by weight of the para-menthylcyclohexanol I which was employed. f

, For reasons which are pointed out hereinafter in greater detail, it is substantially impossible to use conventional methods and obtain a. single glycol ether of the kind described. Actually, one obtains a cogeneric mixture of closely related or touching homologues. These materials invariably have high molecular weights and cannot be separated from one another by any known method without decomposition. The properties of such a mixture represent the contribution of the various individual members of the mixture.

Although one cannot draw a single formula and say that by following such and such procedure, one can obtain or or of such single compound, yet one can readily draw the formulae of a large number of compounds which appear in some of the mixtures described elsewhere, or can be prepared readily as components of mixtures which are manufactured conventionally. Such formulae, representing significant portions of various mixtures are of distinct value, insofar that they themselves characterize the invention, i. e., describe individual components which are typical of the members of the cogeneric mixture. In the following formulae, since ROI-I can represent para-menthylcyclohexanol, R10 is the ether radical obtained :easssasii para-menthylcyclohexanol by removal of the hydrogen atom-attached to the oxygenatom.

(1) 'taorcsnfiomrcznro)an 1(2) 'nmcintoimoimomn 1(3 1R0 ('CHcO) 23 ((321140 an (4) R0. (CsHcOhi (CzI-LrO) 23H .one selects any; hydroxylated compound and subjects such compound to oxyalkylation, such as oxyethylation 'IOI oxypropylation, it "becomes obvious that one is really producing a polymer of :the'allkylenev oxide,-except.for the terminalgroup.

This is particularly true where the amount of oxide added is comparatively large, for instance,

.does not obtain a single constituent, which, for

the sake of convenience, may be indicated as RO(C2H40)30H. Instead, one obtains a cogeneric mixture of closely related homologues, in which the formula may be shown as the following: RO(C2H4O)12H, wherein n, as far as-the statistical average goes, is 30, but the individual members present in significant amount may vary from instanceswhere n hasa value of 25 and perhaps less, to apoint where 11. may represent 35 or more. Such mixture is, as stated, a cogeneric, closely :related series 10} touching homologous compounds. Considerable investigation has been made in regard to the distribution curves for linear polymers. Attention is directed to the article entitled Fundamental Principles of Conidensation Polymerization, by Paul J. Flory, which appeared in Chemical Reviews, volume-89, No. 1, page 137.

Unfortunately, as has been pointed out by Flory and other investigators, there is no satisfactory method, based on either experimental or mathematical examination, of indicating the :exact proportion .of the various members of touching homologous series which appear in -cogeneric condensation products of the kind described.

This means that from the practical standpoint, i. e., the ability to describe how to make the product under consideration and how to repeat such production timeuafter time with- .out .diificulty, it is necessary to resort to some other method of description.

:Actually, from a practical standpoint, it is much more satisfactory, perhaps, to describe the ultimate composition in terms of the reactants, .i.-e., menthylcyclohexanol and the two ahkylene oxides. The reason for this statementis the following: If one selects a specific compound, it

must be borne in mind that such compound is specific only insofar that the cogeneric mixture .interms of a statistical average will conform to this formula. This may be illustrated by an examplesuch as RO(C3H6O)23(C2H4O)2'7H. If one than 50%, actually-one obtains a cogeneric mix- -tureof touching homologues in which the statis- .,tical average does correspond to this formula.

For instance, selecting reactants which, at least theoretically, could give the single compound R (CsHeO) 23'( 021-140) 27H, what actually happens --'is"tha;t one obtains a sort'o'f double cogeneric-mixture, .ior thereason thatineach batch oncon- ",tinuous ,zaddition of alkylene oxide, .a .cogeneric proportions, .based on whole numbers. ,ever, one selects a point in the inner triangular 'mixturetis formed. Since thepresent'products require the addition of.two different: multi-molar proportions of each of two different alkylene oxides (ethyleneoxide and propylene oxide) it be-- comes obvious that a rather complex cogeneric mixture must result.

This canibe best illustrated by example. Assumethat. one is going to use the indicated ratio,

to wit, one .pound of menthylcyclohexanol, .23 pounds of propylene. oxide and 2'7 pounds of ethylene oxide. The initial step involves the treatmentiof one'pound mole of'menthylcyclohexanol with 23 pound moles of propylene oxide so asito yield theoretically RO-(C3HsO)23H; actually, as pointed out, one does not obtain RO(C3H60)nH, in which n is 23, but one obtains a cogeneric mixture, in 'Which there are present significant amounts of homo'logues, in which n varies from 10, 11 and 12 on up to 35, 36 and possibly 40, or beyond. A statistical average, however, must, of course, correspond'to the proportion of the initial reactants, i. e., a-compound of the formula RO(C3Hs0) 23H, whichis present undoubtedly to .a. significant extent.

Whenthis cogenericmixtureis then subjected .to reaction with 27 moles of ethylene oxide, it

becomes obvious that,-although one may obtain .some RO(C3HeO)2z(CzH O) 2 H, 'yet this particular product can'only bepresent'to a minor extent for reasons which havebeendescribed in conin which, as previouslypointed out, components present in important-percentages are those in which n could varyanywhere from 10 or higher,

up to .35 nr+l0. Bythesametoken, components present in important percentages are those :in which could vary anywhere-from 13 or 1&,-and possibly even less, upto 40, 41, i2, .43.or 4.5. .In- .deed, .homologuesof a lower or a higher value of n andn will be presentin'minor. amountsfthepercentages of such-componentsdecreasing, the'further removed they .are .from the average-composition. However, in spite of such variationin regard to the cogeneric mixture, the ultimate composition, based on the ingredients which enterinto it and basedon the statisticalaverage of such constituents, can still beexpressedbythe formula RO(C3H60) 23(C2H4O)27H. This 'actual productexists, tosome degree, in'the cogeneric mixture, but it should belooked upon as a statistical average-formula, rather than the structure of 1 asingle orpredominant compound inthe mixture.

:A'secondreason'ior employing a reaction mixture todescribe theproduct is the fact thatthe molalproportionsineed not represent wholenumbers. We have just pointed out that if one selects molal proportions corresponding to thenthe-constituents are added-in actual molar If, howarea, which, when recalculated interms of molar proportions, produces a fractional number, there is still no reason why such proportion-of initial reactant-should not beadopted. ,-For instance,

tives equally effective.

' one-might selecta-point in the triangular graph,

which, when calculated-in terms of molecular proportions,representsa formula, such as the following: RO(C3H60)23.5(C2H40) 27H. This, of

.course, would be immaterial,- for the reason that if one starts with a pound mole of menthylcyclohexanol and adds 23.5 pound moles of propylene oxide, one will obtain, on the average, a mixture closely comparable to the one previously described, using exactly 23 pound moles of propylene oxide instead of 23.5. Such mixturecorresponds to the compound RO(CsHsO)23.sI- I only in the sense of the average statistical value, but not in the sense that there actually can be a compound corresponding to such formula; Further discussion of this factor appears unnecessary in light of what has been said previously.

Such mixture could, of course,- be treated with 2'7 pound moles of ethyleneoxide. Actually,- all that has been said sums up to this, and that is, that the most satisfactory way, as has been said before, of indicating actual materials-obtained by the usual and conventional oxyalkylation process, is in terms of the initial-reactants, and it-is obvious that any particular point on the triangular graph, from a practical aspect, in-variably and inevitably represents the statistical average of several or possibly a dozen or more closely related cogeners of almostthe same composition, but representing a series of touching homologues. The particularly point selected represents at least the composition of the mixture expressed empiricallyv in the. terms of a compound representing the satistical. average.

Previous reference has beenmade to the fact that comparatively few oxyalkylated derivatives of simple hydroxylatedcompounds find utilityin actual demulsification practice. We have point ed out that we have found a very few exceptions to this rule. The fact that exceptions exist, as in the instant invention, is stillexceedingly difficult to explain, if one examines the slight contribution that the end group derived from the hydroxylated material, makes to the entire compound. Referring, for the moment, to a product of the kind which has been described. and identified by the formula RO(C'3H6O)2,(C'2H4O)27H, it becomes apparent that the molecular weight is in the neighborhood of 2900, and actually, the para-menthylcyclohexanol contributes less. than 10% of the molecular weight. 'As a matter of fact, in other comparable compounds, the para menthylcyclohexanol'may contribute as little as 4% or 5% and yet these particular compounds are efiective demulsifiers. Under such circumstances, it would seem reasonable to except that some other, or almost any other, substituted cyclic G-carbon atom compound comparable topara-menthylcyclohexanol, would yield deriva- Actually, this is not the case. We know of no theory or explanation to suggest this highly specific nature or action of the compound or cogeneric mixture derived'from particularly true if the composition comes within sment of the circle previously refe'rre'dto a the drawing. In such event, one obtains a much more efiective demulsifier than by any other combination employing ethylene oxide alone, propylene oxide alone, or any variation in the mixture of the two, as illustrated by other formulae. In fact, the compound, or cogeneric mixture so ob tained, as far as demulsification is concerned, is not infrequently at least one-third better than any other derivative obtained in the manner described involving any I of the other above variatlons. 1

The significance of what has been said previously becomes more emphatic when one realizes that, in essence, we have found that one isomer" is a more effective demulsifying agent than another isomer. The word fisomer is not exactly right, although it is'descriptive for the purpose intended, insofar that we are not concerned with a single compound, but with a cogeneric mixture which in its statistical average corresponds to such compound. Stated another way, if We start with one pound mole of menthylcyclohexanol, 23 pound moles of propylene oxide and 27 pound moles of ethylene oxide, We can prepare two difierent cogeneric mixtures, which, on a statistical average, correspond to the following:

ject matter of other co-pending applications or under investigation.

Reference has been made to the fact that the product herein specified, and particularly for use as a demulsifier, represents a cogeneric mixture of closely related homologues. This does not means that one could not use combinations of such cogeneric mixtures. For instance, in the previous table, data have been given for preparation of cogeneric mixtures which statistically correspond, respectively, to points I, 3 and 6. Such three cogeneric mixtures could be combined in equal weights so as to give a combination in which the mixed statistical average would correspond closely to point 1.

We need not add that instead of subjectin menthylcyclohexanol alone to oxypropylation and oxyethylation, one can employ a mixture of menthylcyclohexanol along with some other desired reactant, such as alpha-terpineol; For a number of reasons, it is ordinarily desirable to use a procedure in which only one product is reacted'at a time.

Conventional demulsifying agents employed in the treatment of oil field emulsions are used as such, or after dilution with any suitable solvent,

such as water, petroleum hydrocarbons, such as benzene, toluene, xylene, tar acid oil, cresol, anthracene oil, etc. Alcohols, particularly aliphatic alcohols, such as methyl alcohol, ethylalcohol, denatured alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, etc., may be employed as diluents. Miscellaneous solvent s,. such as pine oil, carbon tetrachloride, sulfur diox- V ide extract obtained in the refining of petroleum, etc., may be employed as diluents. Similarly, the

material or materials employed as the demulsifyingagent of our processmaybe admixed with one or more of the solvents customarily used in connection with conventional demulsifying agents. Moreover, said material or materials may be used alone or in admixture with other suitable well-known classes of demulsifying agents.

It is well known that conventional demulsifying agents may be used in a water-soluble form, or in an oil-soluble form, or in a form exhibiting both oiland water-solubility. Sometimes they may be used in a form which exhibits relatively limited oil-solubility. However, since such reagents are frequently used in a ratio of 1 to 10,000, or 1 to 20,000, or 1 to 30,000, or even 1 to 40,000, or 1 to 50,000, as in desalting practice, such an apparent insolubility in oil and water is not signiflcant, because said reagents undoubtedly have solubility within such concentrations. This same fact is true in regard to the material or materials employed as the demulsifying agent of our process.

Ii -practising our process for resolving petroleum emulsions of the water-in-oil type, a treating agent or demulsifying agent of the kind above described is brought into contact with or caused to act upon the emuslion to be treated, in any of the various apparatus now' generally used to resolve or break petroleum emulsions with a chemical reagent, the above proce'durebeing used alone or in combination. with other demulsifying procedure, such as the electrical dehydration process.

One type of procedure is to accumulateavolume of emulsified oil in a tank andv conduct a batch treatment type Of demulsification procedure, to recover clean oil. In this procedure the emulsion is admixed with the demulsifier, for example by agitatingthe tank of emulsion and slowly dripping demulsifier into. the. emulsion. In. some cases mixing is achieved. by heating the emulsion while dripping in. the demulsifier, depending upon the convection currents in the emulsion to produce satisfactory admixture. In a third modification of this type of treatment, a circulating pump withdraws emulsion from, e. g., thebottom of the tank, and re-introduces it into the top of the tank, the demulsifier being added, for example, at the suction side of said circulating pump.

In a second type of treating procedure,.the

demulsifier is introduced into the well fluids at the well-head or at some point between. the wellhead and the final oil storage tank, by means of an adjustable proportioning mechanism or proportioning pump. Ordinarily the flow of fluids: through the subsequent lines and fittings suflices to produce the desired degree of mixing of demulsifier and emulsion, although in some instances additional mixing devices may be introduced into the flow system. In this general procedure, the system may include various mechanical devices for withdrawing free water, separating entrained water, or accomplishing quiescent settling of the chemicalized emulsion. Heating devices may likewise be incorporated in any of the treating procedures described herein.

A third type of application (down-the-hole) of demulsifier to. emulsion is to introduce. the demulsifier either periodically or continuously in diluted or undiluted form into the Well and. to allow it to come to the surface with the well flu-ids, and then to flow the chemicalized' emulsion through any desirable surface equipment, such as employed in the other treating procedures. This particular type of applicationis decidedly useful when the demulsifier-is used in connection with, acidification of calcareous oil-bearing strata;

especially if. suspended in or dissolved in the acid employed for acidification.

In all cases, it will be apparent from the foregoing descriptioin, the. broad process consists simply in introducing a-relatively, small proportion of demulsifier into a relatively large proportion of emulsion, admixing the chemical and emulsion either throughnatural flow or through special apparatus,- with-or without the application of heat, and allowing the. mixture to stand quiescent until the undesirable water content of the emulsion separates and settles from the.

mass.

The following is a typical installation:

A reservoir to hold-the demulsifierofthe kind described (diluted orundiluted) is placed at the well-head where the eflluent liquids leave the well. This reservoir or container, which may. vary from 5 gallons to 50 gallons for convene ience, is connected toa proportioning pump which injects the demulsifier drop-wise into the fluids: Such chemicalized fluids pass.-

leavingthe well. throughthe flowline-into asettling tank. The

settling tank consists. of a tank of any conven ient size,- for instance, one which will hold amounts of fluidproduced in 4 to 24 hoursv (500 barrels to 2000 barrels. capacity),.and in which there is a perpendicular conduit from the top of the tank to almostthe'very bottom so asto:

the fiuids'from the well to the settling tank may includea section of pi'pewith bafiles to serve as a mixer, to' insure thorough distribution of the demulsifier throughout the fluids, or a heater for raisingthe temperature of the fluids to some convenient-temperature; for instance, to F., or both heater and mixer.

Demulsification procedure is started by simplyv setting the pump so as to feed a. comparatively large'ratio of d'emulsiflenfor instance, 115,000. As soon as a complete. break. or satisfactory demulsification is obtained, the pump is regulated until experience shows that the amount of demulsifier being addedisjust sumcient to produce clean or dehydrated oil. Theamount being fed at such stage is usually 1210,000, 1-:15,000,,1-:20,000, or thev like.

In many instances the. oxyalkylated productsv herein specified as demulsifierscan-be conveniently used without dilution. However, as previously noted, they may be dilutedas desired with any suitable solvent. For instance, by

'75 parts byweight-ofan oxyalkylated derivative,

for. example, the product ofExample 1, with-15- parts by weightof xylene and lo partsby Weight of isopropyl alcohol,v anexcellent demulsifier is obtained. Selection-.ofthe solvent will vary, dependingu-pon the solubility characteristics of the oxyalkylated product, and of course, will be 13 dictated in part by economic considerations, 1. e. cost.

As noted above, the products herein described may be used not only in diluted form, but also may be used admixed with some other chemical demulsifler. For example, a mixture which exemplifies such combination is illustrated by the following:

Oxyalkylated derivative, for example, the product of Example 1, 20%;

A cyclohexylamine salt of a polypropylated naphthalene monosulfonic acid, 24%;

An ammonium salt of a polypropylated naphthalene mono-sulfonic acid, 24%;

A sodium salt of oil-soluble mahogany petrole um sulfonic acid, 12%;

A high-boiling aromatic petroleum solvent, 1

Isopropyl alcohol, 5%.

The above proportions are all weight percents.

Throughout the specification elsewhere reference has been made to homologues. It is quite likely that it would be equally proper in numerous instances, and perhaps all the herein described products, to refer to isomers as well as homologues. The reason for this statement is that propylene oxide, as differentiated from ethylene oxide, can, at least theoretically, combine with a hydroxylated material ROH to give ,two different derivatives, one being a primary alcohol and the other a secondary alcohol. This is illus trated by the following:

Elsewhere in the specification the word isomer has been used thus: Isomer. It is not believed there is any confusion between such terminology in that particular instance and what is said immediately preceding.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifler including a cogeneric mixture of a homologous series of glycol ethers of para-menthylcyclohexanol; said cogeneric mixture being derived exclusively from para-menthylcyclohexanol,fethyl ene oxide and propylene oxide in such weight proportions so the average composition of said cogeneric mixture stated in terms of initial reactants lies approximately within the segment of the circle in the accompanying drawing inwhich the minimum para-menthylcyclohexanol content is at least 4% and which circle is identifiedby the fact that points I, 3 and 6 lie on its circumierence, and with the proviso that the para-menthylcyclohexanol be reacted first withall the propylene oxide and then with the ethylene oxide.

2. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier including a cogeneric mixture of a homologous series of glycol ethers of para-menthylcyclohexanol; said cogeneric mixture being derived exclusively from para-menthylcyclohexanol, ethylene oxide and propylene oxide in such weight proportions so the average composition of said cogeneric mixture stated in terms of ini tial reactants lies approximately within the triangular area defined in the accompanying drawing by points I, 3 and 6, and with the proviso that the para-menthylcyclohexanol be reacted first with all the propylene oxide and then with the ethylene oxide.

3. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier including a cogeneric mixture of a homologous series of glycol ethers of para-menthylcyclohexanol; said cogeneric mixture being derived exclusively from para-menthylcyclohexanol, ethylene oxide and propylene oxide in such weight proportions so the average composition of said cogeneric mixture stated in terms of initial reactants lies approximately within the triangular area defined in the accompanying drawing by points 2, 4 and 5, and with the proviso that the para-menthylcyclohexanol be reacted first with all the propylene oxide and then with the ethylene oxide.

4. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier including a cogeneric mixture of a homologous series of glycol ethers of para-menthylcyclohexanol; said cogeneric mixture being derived exclusively from para-menthylcyclohexanol, ethylene oxide, and propylene oxide in such weight proportions so the average composition of said oogeneric mixture stated in terms of initial reactants lies approximately at point I in the accompanying drawing, and with the proviso that the para-menthylcyclohexanol is reacted first with all the propylene oxide and then with the ethylene oxide.

5. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier including a single cogeneric mixture of a homologous series of glycol ethers of para-menthylcyclohexanol; said cogeneric mixture being derived exclusively from para-menthylcyclohexan01, ethylene oxide and propylene oxide in such weight proportions so the average composition of said cogeneric mixture stated in terms of initial reactants lies approximately at point 1 in the accompanying drawing, and with the proviso that the para-menthylcyclohexanol be reacted first with all the propylene oxide and then with the ethylene oxide.

MELVIN DE GROOTE.

ARTHUR F. WIRTEL.

OWEN H. PETTINGILL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,130,525 Coleman et a1 Sept. 20, 1938 2,176,834 Bruson Oct. 17, 1939 2,213,477 Steindorfi et al Sept. 3, 1940 2,233,383 DeGroote et al Feb. 25, 1941 2,243,330 DeGroote et al May 27, 1941 2,307,058 Moeller Jan. 5, 1943 2,317,726 Boedeker et al Apr. 27, 1943 2,330,474 DeGroote Sept. 28, 1943 2,425,755 Roberts et al Aug. 19, 1947 2,425,845 Toussaint et al Aug. 19, 1947 

1. A PROCESS FOR BREAKING PETROLEUM EMULSIONS OF THE WATER-IN-OIL TYPE, CHARACTERIZED BY SUBJECTING THE EMULSION TO THE ACTION OF A DEMULSIFIER INCLUDING A COAGENERIC MIXTURE OF A HOMOLOGEUS SERIES OF GLYCOL ETHERS OF PARA-MENTHYLCYCLOHEXANOL; SAID COGENERIC MIXTURE BEING DERIVED EXCLUSIVELY FROM PARA-MENTHYLCYCLOHEXANOL, ETHYLENE OXIDE AND PROPYLENE OXIDE IN SUCH WEIGHT PROPORTIONS SO THAT AVERAGE COMPOSITION OF SAID COGENERIC MIXTURE STATED IN TERMS OF INITIAL REACTANTS LIES APPROXIMATELY WITHIN THE SEGMENT OF THE CIRCLE IN THE ACCOMPANYING DRAWING IN WHICH THE MINIMUM PARA-MENTHYLCYCLOHEXANOL CONTENT IS AT LEAT 4% AND WHICH CIRCLE IS IDENTIFIED BY THE FACT THAT POINTS 1, 3 AND 6 LIE ON ITS CIRCUMFERENCE, AND WITH THE PROVISO THAT THE PARA-MENTHYLCYCLOHEXANOL BE REACTED FIRST WITH ALL THE PROPYLENE OXIDE AND THEN WITH THE ETHYLENE OXIDE. 